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clumping of the cauda equina

My name is Mark. On 4/7/97 my L4/5 disc exploded into my spinal canal crushing all the peripheral nerves that make up the cauda equina resulting in a cauda equina syndrome. Recovery has not been optimal, possibly due to the fact that the initial surgery was performed at the wrong level (L5/S1) which was not discovered/corrected until 4/10/97. Residuals include numbness to all L4/5 dermatomes and below bilat., as well as neurogenic bowell/bladder, sexual dysfunction and partial paralysis of both legs, hips, buttocks, ankles & feet. I suffer neuropathic pain for which I am on Rx. I have read in Dr. Young's recent updates about advancements in surgical procedures dealing with the compression on the spinal cord (or in my case the cauda equina) specifically the detethering of the cord. I have had numerous post surgical MRI's, the last one being in January of 2001. The MRI's note "clumping of the cauda equina". Can this detethering surgery help me? Is it accepted surgery at this point or still in a discovery mode? How would I find doctors qualified in this specialized area who perform this surgery? As anxious as I am to better my condition, I am not a "cowboy" and want to make an educated decision with regards to risks/benefits, but can't get to that point until I can get to a doctor who is involved in this area. Any comments/thoughts would be appreciated.

Hi and welcome, Mark. I was recently emailing with Dr. Jim Guest, a neurosurgeon at the Miami Project and he is developing some new surgical procedures for cauda equina. I am going to email him to see if he is willing to answer some questions...

Thank you Dr. Wise Young for your help. I didn't think I would be hearing from you so quickly...shouldn't you be home having dinner!! I look forward to whatever information you can find. Thanks a million.

Cauda equina injuries secondary to discal compression

This response is directed toward some of Mark's questions. Acute disc-related cauda equina compression is a fairly rare but definite clinical syndrome. Many surgeons believe that the potential for recovery is related to the severity of pre-decompression deficits, and to the time delay between onset and decompression. Several experimental studies have shown that time is a critical factor for survival of these nerve roots. In the compression setting, the injury is mainly from ischemia, or lack of blood flow, and it is possible that the roots can "die" and become replaced with fibrotic tissue. Mark has listed neurologic deficit and neuropathic pain as the principle problems and is asking if surgical untethering would be helpful. The short answer is that there is no clear answer. Any surgical intervention on nerve roots risks causing even more scarring. If there is still definite compression, I would favor decompression. But, for nerve root clumping in the setting where some functions are still present, i.e. incomplete injury, I would be reluctant to operate. Having said that "untethering" almost always changes neuropathic pain, and rarely makes it worse. I doubt that untethering alone will lead to much improvement in motor, sensory, and autonomic function and risks worsening these. For neuropathic pain related to incomplete cauda equina injury my basic cascade of therapy starts with common sense then medications such as neurontin and amitriptyline, then narcotics, then a trial of spinal stimulation, then consideration of an intrathecal morphine pump, and finally, dorsal-root entry zone lesions.

Clumping of the cauda equina

Thank you Dr. Quest for taking the time to educate me and thank you Dr. Young. I am already handling the neuropathic pain with Rx's neurontin and Percocet as well as vitamins E & B. It doesn't sound like the surgery is a good idea for me.

Thank you Dr. Quest for taking the time to educate me and thank you Dr. Young. I am already handling the neuropathic pain with Rx's neurontin and Percocet as well as vitamins E & B. It doesn't sound like the surgery is a good idea for me.

Jim, thanks so much for coming to the forums. If you don't mind, I want to try to understand the basis of what you describe, which reflects I think the mainstream of neurosurgery. As you know, the pain is really bad for many people and they are desperate.

1. Is the primary reason for reluctance to operate the fact that there is rescarring?

2. In your opinion, what is the success rate of and risk of complication of surgery?

3. Do you know of or have done a cost-benefit analysis of the procedures that you describe [of neurontin and amitriptyline, then narcotics, then a trial of spinal stimulation, then consideration of an intrathecal morphine pump, and finally, dorsal-root entry zone lesions] versus a surgical lysis procedure?

Question from Dr. Young: "I want to try to understand the basis of what you describe, which reflects I think the mainstream of neurosurgery. As you know, the pain is really bad for many people and they are desperate."

Response: Yes, I see several patients with neuropathic pain and it can be a personal nightmare for them and their families. I am certainly sympathetic to this. I agree that my approach is basically mainstream neurosurgery, but I hope the comments below will enlarge on this mainstream approach.

Q: Is the primary reason for reluctance to operate the fact that there is rescarring?
A: No, not really. It is true that the decision to operate into a region of previous trauma is major and there are many variables in the decision. (This is a complex topic and my comments reflect only my own views and experience both with patients, and in experimental models. Any references to specific products reflects only my current pattern of practice and I have no financial relationship whatsoever with these companies.)
When we speak of tethering we need to clarify if we mean spinal nerve root or cauda equina rootlet. I basically consider the former, as extradural scar and the latter as intradural "arachnoiditis", but that is an oversimplification. I think the general reluctance to perform untethering is related to the following issues:
1) The lack of a breadth of experimental and clinical literature on the topic of post- traumatic tethering. This means that the link between the diagnosis of "tethering", surgical therapy, and outcomes is still rather unclear. Prospective studies are lacking to establish the impact of post-traumatic surgical tethering. I do not think blinded studies are realistic, but many of the associated issues such as pain, spasticity, motor deficit, autonomic instability, and bladder dysfunction need to be more rigorously quantified before and after surgery. In addition there are many subjective symptoms that are hard to quantify. The literature is considerably stronger regarding congenital tethering and provides more definitive direction for surgical decision-making in those cases.
2) The higher surgical complication risks in SCI patients, especially wound problems, DVT, CSF leak, pseudomeningocele, respiratory problems in quadriplegics and higher rates of fusion failure. Surgeons are held accountable for their complications at several levels and consciously, or unconsciously, select patients so as to keep complication rates low.
3) The emotional cost and time investment is generally higher with surgery on SCI patients.
Regarding "rescarring" in the extradural context I have been using Adcon- L, a polymer that appears to reduce scarring, several publications exist discussing its putative effects and is fairly widely used clinically. This gel has been temporarily withdrawn from the market due to a packaging issue but is due for re-release. This gel is not used inside the dura. I have not yet reoperated on a patient in whom I've used it so I cannot personally validate that it reduces scarring. However, spinal root scarring is such a nasty sequelae to surgery that I'll keep using it until something better comes along.
For reconstructive expansile duraplasty following untethering I am using a type of Gortex called "Preclude" as a dural substitute and my limited experience has indicated that it does not adhere very much to the rootlets. However, inside the dura the arachnoid will still scar to itself and root clumping cannot be prevented by any procedure or material that I am aware of. One of my colleagues, who has more extensive experience, Dr. Barth Green, uses frequent postoperative repositioning to reduce the incidence of re-tethering following surgery and he believes this is effective.
Finally, this can be very technically demanding surgery and in persons with incomplete injury, untethering procedures carry risks of added neurologic injury. The procedures can be very long, often exceeding 12 hours, and this increases all the complication risks. Because it is necessary to remove bone in order to access the dura and spinal cord, careful consideration must be given to the impact on spinal stability. Because more and more patients have spinal instrumentation in place, this must sometimes be removed, adding a layer of decision-making complexity. Furthermore, substantial evidence exists that it may not be possible to obtain a good term untethering or syrinx decompression result without correction of spinal deformity and compression. That may mean that a much larger and riskier operation may be required.
Having said all of this and getting back to your original question, yes, an untethering procedure can be followed by a recurrence of tethering due to new scar formation, and this may adversely affect the impact of the surgery. In particular it can limit the durability of the surgical result. However, I think that untethering can be can be followed by an excellent outcome in well-selected patients, and that it is the most appropriate therapy in some patients.

Q: In your opinion, what is the success rate of and risk of complication of surgery? I cannot really do justice to this question since my combined experience is only about 20 cases. My colleague and chairman Dr. Green has published data regarding his clinical experience; TT Lee et al, (1997) Progressive posttraumatic myelomalaicic myelopathy: treatment with untethering and expansile duraplasty. J Neurosurgery 86:624-628. An example of one of my most challenging cases is published in E Belanger, ADO Levi (2000) The Acute and Chronic Management of Spinal Cord Injury, J Am Coll Surg 190: 603-617 [Figure 6]. In the Lee and Green paper, some improvement in motor dysfunction occurred in 79% and pain was improved in 62%. A standardized pain score was not described and ventral untethering was not performed. Their complication rates were low.
It's important to realize that every case is different. Sometimes, untethering can be a straightforward operation. The following things make me think the case and perioperative care will be difficult: quadriplegia, chronic pulmonary problems, uncorrected severe spinal deformity, poor bone quality, substantial narcotic dependence, personality problems and or lack of social supports, anterior spinal cord tethering, a long segment of tethering, multiple previous surgeries.
When the risks are high, then the indication to do surgery must be very clear and I would require clear documented evidence of neurological deterioration before subjecting the patient to the risks of surgery.

I would quote patients a 10- 50% risk of reversible perioperative complications depending on patient and surgical factors. I would quote a 5% risk of major complications. I think that until much more published clinical data is available the predicted success rate must be estimated based on a composite of surgeon experience and the available published experience.

Q: Do you know of or have done a cost-benefit analysis of the procedures that you describe of neurontin and amitriptyline, then narcotics, then a trial of spinal stimulation, then consideration of an intrathecal morphine pump, and finally, dorsal-root entry zone [DREZ] lesions versus a surgical lysis procedure?
A: No, I have not done a cost-benefit analysis and in my situation as a surgeon I am usually referred patients who are not getting very good relief from pain with medications and other non-surgical therapy; therefore that part of the conventional treatment algorithm is not under my control. Medications are expensive. Once again my experience with these procedures is not vast, although I am interested in neuropathic pain. I think that in the long run surgical treatments are good "value" when they work, and the secret is recognizing which treatment is right for a given patient. There are several publications that comment on selecting patients for DREZ lesions. I do not think that we can discuss spinal cord or nerve root untethering as an established therapy for neuropathic pain, although I have seen some very good responses. Morphine pumps and dorsal spinal stimulators are expensive, and the pumps, in particular, require maintenance filling. In appropriate patients DREZ lesions are very effective and I think DREZ is more reliable than untethering to treat neuropathic pain.
I think an issue that influences the response to therapy is how the pain is organized in a given patient's CNS. Functional MRI and other studies of the patterns of brain excitation are teaching us that neuropathic pain is associated not only with local abnormalities of neuronal firing but also with reorganization of brain centers. In some patients a local surgical treatment may fail because a brain pain center has become "autonomous". One way to preselect patients for therapies such as morphine pumps is perform an epidural anesthetic and see if the pain is partially abolished. If a morphine or xylocaine epidural is not effective, the chance that there will be a good response to a morphine pump is diminished. The benefit of the pumps and stimulators is that no tissue has to be destroyed.
So, in summary, I do not know the relative costs and it's obviously difficult to place a value on reducing neuropathic pain. I think we lack unequivocal patient diagnosis and selection techniques and we lack detailed studies on the impact of untethering on SCI patients with neuropathic pain. Until that is available, each surgeon or referring SCI doctor has to exercise his or her best judgment on a case-by-case basis.

Dr. Guest, you mention that one factor in the potential for recovery is the time delay between onset and decompression. What is your counsel in the case of a severe injury (partial paralysis of hips, complete paralysis of legs/feet) that is more than 10 years old?
Thank you.

Dr. Guest, you mention that one factor in the potential for recovery is the time delay between onset and decompression. What is your counsel in the case of a severe injury (partial paralysis of hips, complete paralysis of legs/feet) that is more than 10 years old?
Thank you.

James Guest has not visited this site since 2006, and of course this specific thread is now 10 years old. I would not hold your breath waiting for an answer to this post. Perhaps you should post your question for Dr. Young on a separate thread?